Abrasive devices



E. S- HAVEN ETAL 1 6 9 1 L 1 H M. A

ABRASIVE DEVICES 2 Sheets-Sheet 1 Filed Jan. 27, 1960 FIG.I

INVENTOR. EDWARD S. HAVEN 8| BY 7 RAYMOND ABROOKS .nn in! ATTORNEY April11, 1961 E. s. HAVEN ET AL 2,978,845

ABRASIVE DEVICES Filed Jan. 27, 1960 2 Sheets-Sheet 2 INVENTOR. EDWARDs. HAVEN a y RAYMOND A. BROOKS ATTORNEY ABRASIVE DEVICES Edward S.Haven, Scotia, and Raymond A. Brooks, Latham, N.Y., assignors to NortonCompany, Troy, N.Y., a corporation of Massachusetts Filed Jan. 27, 1960,Ser. No. 5,053

3 Claims. (Cl. 51-193-5) This invention relates to grinding andpolishing wheels formed from a plurality of sheets of flexible coatedabrasive material, wherein the sheets extend radially outwardly of thewheel. Such wheels are generally termed flap wheels.

.Wheels of the type referred to are shown in U.S. patents: 2,651,894;2,818,691; 2,842,902 and others.

Wheels of this type have been particularly useful in certainapplications. However, as is the case with any article which is rotatedat high speeds, a point is reached at which the wheel will explode dueto centrifugal force. Such explosions are of course a serious accidenthazard.

It is therefore, an object of the present invention to provide areinforced flap wheel construction having increased resistance toexplosion at high rotation speeds.

It is a further object of our invention to provide a flap wheelconstruction whereby wide wheels may be constructed which are safe andeconomical.

In the past flap wheels have been constructed by reinforcing the innerends of the flaps with an adhesive, such as glue, or preferably acurable synthetic resin. In some cases the adhesive has been appliedonly to the ends of the flaps, in other cases it has extended for somedistance radially outwardly from the inner ends "of the flaps. Inaddition it has been common practice to reinforce the wheels at thesides, a substantial distance radially inwardly of the wheel, by fittingone or more metal rings in one or more grooves at each side of thewheel. Such construction has proved satisfactory in narrow width wheels.However, with wide wheels, it has been found that additional support isrequired. The present invention provides suchadditional support byintroducing novel support members at the inner circumference of thewheel.

The invention will now be more'fully described, having reference to theaccompanying drawings wherein:

Figure l is a perspective view, with some of the flaps removed for thepurpose of illustration, of an unmounted wheel of the invention.

Figure 2 is a partial cross-sectional view of a wheel showing the innerend of one of the coated abrasive flaps used in a wheel of the presentinvention with part of a reinforcing means shown.

Figure 3 is a view similar to Figure 2, showing the reinforcing means inoperative position.

Figure 4 is a front elevation of an abrasive sheet for a flap wheelhaving three internal sets of reinforcing rings.

Figure 5 is a side view of a reinforcing ring of our invention.

In Figure 1 is shown the completed wheel of the invention having twointernal reinforcing means with a number of flaps removed to moreclearly show the construction. The individual flaps are indicated at 11,each flap being adhesively coated on one side with abrasive grain, theabrasive sides of the flaps all facing in the same direction. On eachside of the wheel adjacent the inner diameter are two grooves orchannels 12 and 13, in at least one of which on each side of the wheelmay be mounted a retaining and forming ring 14. In the inner peripheryof the wheel are shown two channels 16 and 17., the walls of whichdiverge from the inner periphery, radially outwardly in dovetailfashion. Positioned in each groove 16 and 17 are a set of reinforcingrings 18, 19 and 18', 19'.

Each set of reinforcing rings 18, 19 and 18, 19 consists of two halves,identical in shape complementary to the internal shape of the dovetailchannels 16 and 17. One half (18 and 18') in each set has a pluralitydrilled and tapped holes around its inner circumference to receivejacking screws 20' shown in the reinforcing half 18. A similar set ofscrews, not shown in Figure 1, are positioned in reinforcing half 18.With the jacking screws retracted, the ring set can be placed togetherface to face and the cross sectional dimension is then small enough topermit initial positioning of the flaps on the reinforcing rings. Whenall of the flaps have been positioned around the reinforcing rings thejacking screws are then turned in forcing the two halves apart untilfull engagement of the rings with the respective dovetail notches isachieved.

Figure 2 shows a single flap 11 of a modified wheel having a single setof internal reinforcing rings. Notches 22 and 23 are cut in each flap toform corresponding grooves similar to grooves 12 and 13 in Figure 1. At26 is an internal dovetail notch in which rings 28 and 29' are mountedsimilar to rings 18 and 19 of Figure 1. In groove 26 is shown the ringassembly 28, 29 in retracted position prior to turning of the jackingscrews 30.

Figure 3 shows a fragmentary cross-sectional view of a flap wheelwherein the jacking screws have been operated to expand the ringassembly 28, 29.

Figure 4 illustrates a form of abrasive flap used in wide wheels of ourinvention where three internal reinforcing ring sets may be employed.The flap 41 is provided at each side with notches 43 and 44. Along thebottom edge of the flap are provided three dovetail cuts 46, 47 and 48in which reinforcing ring sets similar to rings 18 and 19 of Figure lare mounted. As will be apparent, a plurality of sheets 41 are formedabout three reinforcing rings to form an annular Wheel similar to thatof Figure 1.

In Figure 5 is shown a side view of a reinforcing ring 58 employed inthe wheels formed from flaps such as shown in Figure 4. The ring isprovided with tapped holes '50 to accommodate jacking screws 51. Inaddition, access holes 52 are provided for insertion of a tool toactuate the jacking screws of the internal reinforcing rings. The ring58 cooperates with a similar ring, but not provided with tapped holes,against which the jacking screws abut to expand the ring set.

The provision of the access holes is essential Where more than tworeinforcing rings are employed since the inner ring or rings areotherwise inaccessible when the flaps 41 have been positioned about thereinforcing rings. By providing such access holes and by properly liningup the jacking screws of the internal rings, any desired number of setsof internal reinforcing rings may be provided in a wheel.

In assembly wheels made according to the present invention, the internalreinforcing rings are mounted on a vertical support, spaced the properdistance apart and held temporarily in place by frictional contact,detent or other means, with the vertical support while the abrasiveflaps are arranged about them. When a suificient number of flaps havebeen inserted to form a wheel of the desired density, rings 14 may beinserted at each end of the wheel to add. support and to help align theflaps,

ze'rsese a? When all the flaps are arranged in place, the jacking screwsin the reinfo rcin g rings are rotated to expand the reinforcing ringsinto snugiengagernent with the dovetail grooves.

Finally, adhesive ,is applied to theinner ends of the flaps 11 andallowed to penetrate radially outwardly of the inner ends of the flapsto a depth approximately equal to the depth of the dovetail grooves;This can readily be accomplished by temporarily capping the ends of thewheel, pouring the liquid resin at the desired locations at the innerannulus of the wheel and rotating the Wheel about a horizontal axis. I

As an example of the type of wheel which can be satisfactorilyconstructed according to my invention, approximately 95 0 sheets of a120 grit silicon carbide coated J'weight cloth backed coated abrasiveare em ployed. The sheets, for example, are 10 inches in width andabout5% inches l.ong, having notches 16 and 17 at their base and notches 12and 13 at their sides. The sheets are formed into an annulus about thereinforcing rings 18, 19, and 18, 19' with the aid of an assemblyfixture and the reinforcing and retaining rings are insertedas abovedescribed. Adhesive is then applied in the manner described above to theinner ends of the flaps and cured. The finished wheel is 10 inches wideand about 16 inches'in diameter. It can be run without breaking atspeeds as high as 2700 r.p.m. Standard end plates which mate with thegrooves 12 and 13 are mounted at each side of the wheel when the wheelis in operative position on a shaft, ready for use.

We claim:

1. An annular abrasive wheel comprising a plurality of abrasive coatedsheets, said sheets being secured in an annular row, each side of saidwheel being provided with at least one annular groove having areinforcing ring positioned therein, at least one annular groove in theinternal periphery of said wheel, said grooveb'eing narrowest at itsinner diameter and widest at its outer diameter, and a reinforcingmember positioned in said groove, said reinforcing member conforming tothe shape of said groove.

2. An annular abrasive wheel comprising a plurality of abrasive coatedsheets, said sheets being secured in an annular row, at least oneannular groove in the internal periphery of said wheel, said groovebeing narrowest at its inner diameter and Widest at its-outer diameter,an annular reinforcing means positioned in said groove, said,reinforcingmeans being expanded from an initial condition whereby it is narrowerthan said groove to an operative position whereby said-reinforcing meansis locked in said groove.

3. An annular abrasive wheel comprising a plurality of abrasive coatedsheets, said sheets being secured in an annular row, at least threeannular grooves in the internal periphery of said wheel, each of saidgrooves having a lip narrower than the internal width of said groove, anannular reinforcing means positioned in each groove and operative froman initial condition whereby the maximum width of said reinforcing meansis smaller than the Width of said lip to an expanded condition wherebyeach reinforcing means is locked in its respective groove, accessopening in at least one of said reinforcing means to permit entry of atool for operating an adjacent reinforcing means from said initial tosaid expended condition.

References Cited: in the file ofthispatent UNITED STATES PATENTS2,808,689 Thomson et al. Oct. 8, 1957

